Sludge management in Jordan: Sustainability through innovation
Title: Decentralised Integrated Sludge Management (DISM)
Commissioned by: German Federal Ministry for Economic Cooperation and Development (BMZ)
Lead executing agency: Water Authority of Jordan
Overall term: 2015 to 2020
There are 31 Wastewater Treatment Plants (WWTPs) in Jordan. The largest is As-Samra, which treats around 60 per cent of the total wastewater generated in the country. Only two of the facilities, As-Samra and Al Shallaleh, utilise sludge as an energy source. None of the other 29 WWTPs implement a proper Sludge Management Plan (SMP), where the accumulated sludge is a major source for health and environmental risks that contribute to Greenhouse Gas (GHG) emissions. As such, the challenge resides in shifting the focus on utilising sludge as an alternative energy resource and a means of combating desertification rather than a wasteful product to be discarded.
Jordan also faces major challenges in handling other sources of biomass. Local Municipalities do not have adequate Solid Waste Management (SWM) systems nor the required infrastructure in place to manage the generated biomass, resulting in dumpsites that are not engineered or lined, leading to environmental risks such as groundwater pollution.
An integrated approach has been put in place for the treatment and reuse of sludge in order to tackle the problems of sludge collected in wastewater treatment plants and to contribute to the reduction of CO2 emissions.
On behalf of the German Federal Ministry for Economic Cooperation and Development (BMZ), Deutsche Gesellschaft für Internationale Zusammenarbeit (GIZ) GmbH is supporting the Water Authority of Jordan (WAJ) in its efforts to find suitable solutions for the treatment and reuse of sewage sludge. The project is part of the German Climate Technology Initiative (DKTI), which promotes the adoption of climate technologies in emerging economies and developing countries, thereby linking climate protection, sustainable development and poverty reduction.
The project aims to reduce the carbon footprint of sludge handling by demonstrating an integrated approach towards collecting, treating, digesting and co-digesting, and then re-using sludge in limited land applications. While primarily tapping the potential for energy, residual sludge is also co-processed with food waste to produce a Treated Organic Mix (TOM) which can then be used as a soil conditioner. This integrated approach guarantees the inclusion of all relevant stakeholders, such as the respective ministries and municipalities, water utilities, and farmers.
In 2015, the project started some pilot activities at the Mu’ta – Mazar WWTP in the Karak Governorate, 135 km south of Amman, and in 2019 extended its interventions to the North Aqaba WWTP (NA-WWTP) in the Aqaba Governorate, around 350 km south of Amman. The chart below shows sources of GHG emissions in Mu’ta – Mazar WWTP.
The Project will ensure the safe usage of sludge by developing a comprehensive Risk Management System (RMS) for land applications of treated sludge and TOM as soil conditioners.
The Project also works to increase awareness on sustainable sludge management among key stakeholders by piloting a lab-scale co-digestion prototype and developing a university learning module to be taught at Mu’ta University.
Sludge Digestion and Co-digestion
The project works in cooperation with the WAJ and the Aqaba Water Company (AWC), supports in contributing to the modification of sludge line at the current NA-WWTP to enable the utilisation of sludge in the new NA-WWTP biogas plant. This will result in a more than 30 per cent increase in energy generation.
The project, in cooperation with Prince Faisal Centre at Mu’ta University has also designed, constructed, and operated an anaerobic co-digestion prototype reactor at the Centre’s labs to investigate more feasible solutions for sludge accumulation. The project has also installed digestion prototypes (Biogas Test Plants) at the Mu’ta – Mazar and NA WWTPs. Such investigations included the assessment of processing sludge with different sources of organic waste, applying different mixing percentages, and operational conditions in order to define optimal biogas yields.
The Project team, in collaboration with the Mu’ta – Mazar WWTP lab team, also carried out experiments to test three mixing ratios of sludge to food waste to cooked oil (100:0:0, 80:20:10, & 50:40:10 respectively). Results have shown that the best mixing ratio was 50:40:10, which produced a Methane yield of approximately 93 per cent.
Risk management system
Unless managed properly, producing and handling treated sewage sludge and re-using it in land applications can present a health and safety risk to both the public and the environment. It is therefore important that systems are in place to monitor the quality of sludge produced and ensure that pollutants do not exceed limits. The Royal Scientific Society (RSS) has monitored the quality of sewage sludge produced at the Mu’ta – Mazar WWTP since 2017, and has concluded its compliance to all necessary standards (Types I & II, JS 1145:2016). The material can now be either landfilled or applied to land with a rainfall of less than 200 mm/year for soil conditioning. At the same time, TOM was rated as “good” against the JS 1145:2016 quality requirements for bio-solids.
The Project developed a Risk Management Framework for sewage sludge management, in conjunction with many national parties for regulatory, health, environmental, research, operational and monitoring aspects, that uses Mu’ta - Mazar WWTP as a study case.
Moreover, the Project carried out a land application experiment in Ghweir Agricultural Station in Karak (2017-2019), in cooperation with the National Agricultural Research Centre (NARC), in which different rates of sludge and TOM were applied and compared to results from using fertilisers. In all cases, productivity was greater than was achieved by using fertilizer. Irrigated Sorghum was 3.6 per cent (fresh yield) higher in Season I; rain-fed barley (biological yield) was 28 per cent higher using sludge and 2 per cent higher using TOM in Season II; and irrigated Sorghum was 96-236 per cent (fresh yield) higher using sludge and 76-168 per cent (fresh yield) higher using TOM in Season III. While in season IV, Sorghum showed 37-61 per cent fresh yield increase using sludge, and 16-53 per cent increase using TOM.
In 2017 and 2018, the Project intensified its efforts to increase the number of subscribers in districts served by the Mu’ta - Mazar WWTP. This included public awareness campaigns on the health and environmental risks and impacts of cesspools, and regulations for household connections. 1,650 home visits were carried out, which reached 2,850 people. As of June 2019, a total of 2,525 households have been connected to the sewage network and are being serviced by the WWTP, which accounts for approximately 54 per cent of the total population in the 5 municipalities. As a result, the number of cesspits was reduced, the efficiency of the Mu’ta - Mazar WWTP was increased, and the quantity of re-usable treated wastewater downstream increased.
The Project is facilitating research on the co-digestion and sustainable reuse of sludge. It has also developed different public educational materials, as well as a university learning module on Sludge Management that is being taught at both Bachelor and Master levels in the Faculty of Engineering at the Mu’ta University. A total of 31 undergraduate and 17 graduate students enrolled in the course during the second semester of 2019 and, upon evaluation, 54 per cent of students reported that they had increased their knowledge in this area. The module will continue to be taught in future semesters.